| 摘要 |
PROBLEM TO BE SOLVED: To provide the picture processor which is free from the reciprocal relation between the resolution and the number of reproducing gradations and stably obtains a high-quality output picture. SOLUTION: A figure (a) shows a screen pattern of screen angleθ=76 deg., and a density threshold S is stored correspondingly to each of subpixels constituting this pattern. An input picture signal V (density 130) is compared with each density threshold S to determine the density of each sub-pixel. Normally, the density of the subpixel is set to a maximum (255) or a minimum (0). However, one subpixel meeting a prescribed condition is set to an intermediate density (170). The density of each subpixel is compared with a triangular wave, and a modulation signal of a laser diode is generated in accordance with the comparison result. In this case, the triangular wave signal related to the subpixel set to the intermediate density is so set that both of adjacent sub-pixels are continued when subpixels adjacent in the main scanning direction have the maximum density.
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